The invention generally relates to tactile sensors, and, more specifically, to tactile sensor systems that provide continuous measurement over objects having surface areas larger than the sensor contact area.
U.S. patent application Ser. No. 12/488,008 filed on Jun. 19, 2009, discloses a tactile sensor includes a photosensing structure, a volume of elastomer capable of transmitting an image, and a reflective skin covering the volume of elastomer. The reflective skin is illuminated through the elastomer by one or more light sources, and reflects light back toward the photosensing structure. The reflective skin and underlying elastomer can conform to a target surface during contact. The resulting geometrical alterations cause localized changes in the surface normal of the reflective skin, resulting in similarly localized changes in the amount of light reflected from the reflective skin in the direction of the photosensing structure. These variations in light intensity encode three-dimensional data for the measured surface, which can be calculated as surface normals, a gradient map, a three-dimensional surface map, or any other suitable representation.
While techniques exploiting the properties of such a system are generally described in the applications described above, there remains a need for adaptations of this technique to facilitate the continuous capture of surface data over surfaces larger than the surface area of the tactile sensor.